Many studies have looked at knee motion and strength after surgery to repair the knee. There are six different knee motions to consider: flexion (bending), extension (straightening), side-to-side motions, and turning (rotation) in and out.
Three months after surgery, flexion and side-to-side motions start to return to normal. By six months, the other motions also show improvement. After one year, muscle strength in all six directions has improved. The last movement to return to normal is usually extension.
You won't be able to judge the final outcome for another six months. If there is a big difference between your operated leg and your other leg, talk to your doctor. A physical therapist can test the strength and motion of your legs and offer exercises that may be more appropriate for this phase of recovery.